import java.util.List;
import java.util.TreeSet;

public class TreeSetDemoTest {

    public static void main(String[] args) {

        TreeSet<Student> tSet = new TreeSet<>((s1, s2) -> Integer.compare(s1.getId(), s2.getId()));
        Student st1 = new Student(1, "Nguyen Van A", "FJB01", 6);
        Student st2 = new Student(2, "Nguyen Van B", "FJB01", 8);
        Student st3 = new Student(2, "Nguyen Van C", "FJB02", 4);
        Student st4 = new Student(4, "Nguyen Van D", "FJB02", 10);
        Student st5 = new Student(5, "Nguyen Van E", "FJB03", 8);

        System.out.println(tSet.addAll(List.of(st1, st2, st3, st4, st5)));
        st1.setId(69);
        tSet.add(st1);
        tSet.forEach(System.out::println);

        for (Student student : tSet) {
            System.out.println(student == st1);
        }
    }
}